topic Re: Perpendicular constraints bug in Fusion Support Forum

Perpendicular constraints bug

Anonymous — Thu, 10 May 2018 10:13:14 GMT

Hi there, I have a critical bug in the sketch of one of my designs.

When I draw two lines and set "perpendicular constraints" between them, they are not perpendicular. When I quote the angle it is different from 90° and more quotes of the same lines give different values.

Even if I set the horizontal/vertical constraints the two lines are not perpendicular to each other. It seems that world axes are not perpendicular between them.

I attach some screenshot to show you 3 different measurements of the same angle (watch the value in the bottom right corner of the window).

Thank you very much.

Frank.

Re: Perpendicular constraints bug

jeff_strater — Thu, 10 May 2018 13:32:54 GMT

The sketch solver is only guaranteed to be accurate to 10-6, so these results are not completely unexpected. However, let me look into this a bit more closely, because of the different values for different selections. We have uncovered a few inaccuracies in how Measure reports values, and I suspect these may be related.

Jeff

Re: Perpendicular constraints bug

Anonymous — Thu, 10 May 2018 14:24:16 GMT

Thank you Jeff for your reply, but the problem I think it's a little more complicated. It's not easy to explain but I want to try...

Usually (thanks to God) when I make a new design and start a new sketch inside, I draw lines and put constraints without problems and without thinking so much. For example, I make a square, exit sketch, extrude it and I have a beautiful perfect box.

In some cases (and this is one of them) I draw a square putting constraints but, when I extrude it, the box is not orthogonal. A face is longer than the "parallel" face. Or if I draw 2 squares and extrude 2 boxes, when I select "parallel" faces of box 1 and box 2, in the bottom-right corner Fusion gives me an angle instead of the distance.

In conclusion, this problem sometimes causes me design bugs, difficult to discover. I would just like to make you understand that this is not my fussiness.

Thank you again.

Frank

Re: Perpendicular constraints bug

jeff_strater — Sat, 12 May 2018 23:20:00 GMT

It turns out that this is a bug in the Measure code. The lines are definitely perpendicular, but when measuring between two entities, the graphical representation is used to calculate the distance/angle/etc. The graphical representation is not quite as precise as the underlying curves/lines/etc. So, when you select the line at different places along its length, you will get different measurements. We will work towards fixing this problem, and thank you for pointing it out.

Jeff

Re: Perpendicular constraints bug

Anonymous — Fri, 01 Jun 2018 21:35:15 GMT

I am also finding a problem, when i draw a sketch with the line tool, first horizontal then vertical i do not get a 90 degree square constraint shown? just the perpendicular marker?

I'm new to Fusion360 what am i missing?

Re: Perpendicular constraints bug

rishabh.bisht — Thu, 29 Nov 2018 04:21:00 GMT

This issue with the Measure command should be fixed with the November release. Please let us know if you still encounter this issue.
Thanks!